What causes dieseling..

[jeepthing]

At least I think that's what it's called. When I turn of my GW after driving for a while...it doesn't shut off right away, but continues for a few seconds then finally shuts off. Just started doing this by the way... I was recently playing with the timing, and returned it to what it was when I bought it (or at least I thought I did)

[joe]

Originally posted by jeepthing:
I was recently playing with the timing, To far advanced will for sure cause dieseling.

[alex.t]

I think carbon build up will also cause dieseling. As I understand it, the carbon deposits build up heat and get hot enough to ignite fuel after you shut off the ignition.

[Don S]

Originally posted by alex.t:
I think carbon build up will also cause dieseling. As I understand it, the carbon deposits build up heat and get hot enough to ignite fuel after you shut off the ignition...
alex.t:... Very true...
... A lot of carburetors are equipped with anti dieseling solenoids and it could be out of adjustment or disconnected.
… Carbon is also a big promoter of dieseling…
link> CARBON & FUEL ADDITIVES (http://groups.msn.com/JEEPTECH101/jeeptech.msnw)
Good Luck and CUL ;) … ds..
- - - - - - - - - - - - - - - - - - - - - -
1976 Wagoneer 406 MC4300 TH400 QT TruTrac 2" lift 31x10.50s duel Optimas
It’s taken us over 261 Colorado Mountain Passes since 1985-
link> 2003 OURAY FSJ Invasion Info and High Altitude Tips (http://groups.msn.com/ATexasOklahomaJeepClub/ouraycotopic.msnw)
link> Acronym and Abbreviations for 4X4 Gearheads (http://groups.msn.com/NISSAN4X4TRAILS/acronymlist.msnw)

[kidatforty]

Dieseling, and pre-ignition (pinging) can be caused by several things. Sometimes It's not just one cause. What's happening is the fuel is being ignited even when no spark is occurring.Timing advanced too far, poor grade of gas, running too hot for whatever reason,carburetor idle mixture a little too rich with throttle stop screw adjusted too far,engine built with too high of compession for the octane available. When I go to mexico I retard my timing 5 degrees to compensate for the bad gas.If you run premium gas you can probably have your timing on the high side and run well . If you run low octane then compensate by reducing the timing a little. Make sure you have no vacuum leaks which would cause lean condition and drive up temperatures. If you are positive that you have the timing set according to mfr. then you can assume your problem lies elsewhere. Oh yeah, you have fuel injection-Yes? Leaky injectors will admit fuel in the engine when all is shut off and cause your dieseling as well.If you have dieseling but not pinging then it probably is fuel related. Hope that provides some understanding.